1. Field of the Invention
The present invention relates generally to a stump cutting apparatus and, more specifically, to a tool holder and cutting tool for use with a stump cutting apparatus.
2. Description of Related Art
Various types of stump cutting devices are known. One type includes a rotatable wheel or disk having a plurality of cutting tools fastened adjacent a peripheral edge. A second type includes a rotatable drum having a plurality of cutting tools fastened adjacent to or on an outer circumferential surface. During operation, as the wheel or drum rotates the cutting tools engage and cut the stump. Each type uses a multitude of various cutting tool styles and configurations. A cutting tool typically includes a tool holder secured to the cutting wheel or drum and a cutting tooth secured to the tool holder.
Some stump cutting devices use a pair of tool holders, sometimes referred to as pockets or mounting blocks, attached across from each other on opposite sides of the wheel. Each tool holder typically includes a pair of apertures used for mounting or securing the tool holder to the wheel. Various configurations can be used including the tool holder having two counter bored apertures with the opposite or corresponding tool holder having two threaded apertures. Each tool holder could have one counter bored aperture and one threaded aperture.
A fastener, such as a bolt or screw, extends through the counter bored aperture in the tool holder, an aperture in the wheel and threadably engages the threaded aperture on the opposite pocket. Tightening the fastener draws the opposing tool holders together such that they sandwich the wheel between them.
Tool holders support and secure a cutting tooth to the wheel. Depending upon the cutting tooth design or style a carbide-cutting bit is attached to the cutting tooth. Since stump cutting teeth typically operate in a harsh environment, contact with the ground surface rapidly dulls the cutting edge of each cutting tooth. When a cutting tooth strikes something hard such as a stone or rock the cutting bit or an edge may break or chip requiring replacement of the cutting tooth. Finally, continuous loading of the cutting tooth can cause cutting tooth failure including twisting or bending of the shank portion. In some instances, the tooth itself may break thus necessitating replacement. Replacement of the cutting teeth is or can be an almost continuous job. Cutting tooth replacement is costly both in material replacement costs and in associated man-hours necessary to remove and install each individual new cutting tooth. Further, depending upon the load applied to the cutting tool during the stump cutting operation, the fastener securing the tool holder to the wheel may break or shear.